Furnace



Aug. 2o, v1929.

c. H. CARPENTER ET ALA FURNAGE FiledMaroh 27, 1928 2 sheets-snm -1 l,lfzlllllll/llflllrf//f/ y ATTORNEY Aug. 1929.

C. H. CARPENTER ET AL FURNAGE 2 Shets-Sheet ,2

Filed March 27, 1928 fig- f INVENTORS Cmnsonh, Corpemer and @Af/)7D /eene.

' ATTORNEY Y l door openings in" furnaces without hinder- Patented Aug; zo, 1929.;

UNITED STATES PATENT oFFic-E.

CRAINSTON H. vGAIBPENTIEB. -ANZI) ALVIN D. KEENE, Ol' 4lLA-N'SFIFILCD, OHIO, ASSIGNOBS T0 WESTINGHOUSE ELECTRIC AND MANUFACTUBINGCOHPANY, A OOBPOBATION or riiNNsYLvmA.

Appiieatioa nica Haren 27,

' Ourinvention relates to furnaces and p'articularly to means forchecking or preventing the loss of heat through door openings of the furnaces caused by the natural circulation of air from the atmosphere outside of the furnace, through the door openings and out to the atmosphere,`as heated air. Y

An object of the invention is to provide means for checking or .minimizing the loss of heat, inthe f orm of heated air, through.

L ing or obstructing the movement of material, to be heated' in the furnace, through the openings. t

Another object of the invention is to lsubstantially Acheck the escape of heat, in the form of heated air, fromfurnaces through their door openings while material to be heated is being inserted and withdrawn from the furnaces through the openings.

A further object of the invention is to provide for the circulating of air within furnaces and'sodirecting its flow that a wall or screen of continuously circulating air is effected near the door openings or the entrances to the furnace to substantially prevent the ingress and egress of air to and from the furnace; and

A further object of the` invention is to Y provideaplurality of spaced walls of circulating air disposed adjacent to openings in furnaces and in planes adapted to obstruct the natural circulation of air from the outside atmosphere through the furnace :and out to the atmosphere, whereby heat losses from the furnaces, in the nature of heatedy air, are substantially reduced, and vfor practical pur- 4 poses prevented. Fora fuller understanding of the invention, reference may be had to the following descriptionztaken in conjunction with the ac-r companying drawings, in which:

air, disposed near the openings l igure 1 is a view, in section, of a furnace structure embodying the invention, taken on Y line I-I of Fig. 2;

Fig. 2 is an enlarged view, in section, of the same structure taken on line II-I of Fig.1;and i Fig. 3 is a partial, enlarged longitudinalA view, in section,'ofth'e furnace structure illustrated in Figs. 1 and 2, showing diagrammatically the effect of circulati g walls of xltov the furnace, upon the natural' circulation of air rUnNAcn 1928. Serial N0. 265,055.'

tom and side walls of suitable refractory heat resistant material.

a'wall 2v of suitable refractory heat resistant material that extends from the top to the The central porvtion of` the furnace structure is provided with bottom walls, thereby defining two separated l passagewa s or tunnels 3 and 4 at the middle portion 'the furnace. furnace may be provided with intermediate walls 5 and 6 for supporting thetop Wall of the furnace at the ends thereof.

'I he furnace may be heated electrically by resistors 7 8, 9 and 1() which may be suspended from the side walls and the wall 2 in any suitable manner. In the preferred form of the invention, the resistors may be of such material' as nickel chromium, in

Vribbon form, and may be supported by lugs 11 projecting from the walls. The lugsmay be of thesame material as the walls 4of the furnace,1 provided the material p proper electrical'-insulatingV properties.

In order that material to be heated in the furnace may be conveyed therethrough, endless conveyors comprising tracks 12 and 13, respectively, each provided with a plurality of carriers 14 and 15, only one of which is shown on each track, are provided, thecarriens 14 may be connected together by exible chains or any other suitable means of coupling. The carriers 14- and 15 may be` provided with hooks 16 which project into the furnace chambers or tunnels 3 and 4' through slots 17 and 18, respectively, which extend the full length of the top wall of the furnacel.

Since the resistors 7, 8, 9 and 10 are located` atsubstantially the middle portion'of the furnace structure '1,' the temperature within the furnace will be a maximum'at its middle portion, anda minimum out at the ends thereof. Therefore, the temperature at any point between the middle and the ends of the furnace will be an inverse function of the distance from the middle section in which the resistors are located.

In the particular furnace lstructure illustrated in the drawings, both of its ends are open in order that the conveyor hooks 16 The ends of the may travel continuously through the tunnels atmosphere.

or chambers 3 and 4. Since the ends of the furnace are open and since the temperature within the furnace is high relatively to the atmosphere' surrounding the furnace walls, cold air will enter through the bottom portion of the .furnace openings and iiow along nace chambers or tunnels -3' and 4, expand and travel outwardly towards the end of the furnace and through the openings to the It has been found that'the heated air leaving the furnace travels at a rate of approximately 300 feet per minute under certain conditions of operation. Since theV furnace chambers are relatively large in volume, a large number of Cubic feet of air will circulate through the furnace and carry of heat, thereby reducing the efiiciency ofthe furnace and also its temperature.

In order to check or prevent the circulation of air from the atmosphere into the furnace chamber and 4out again to the atmosphere, a plurality of blowers 19, 20, 21 and 22 are provided. As shown, the blowers are supported von the 'top wall of the furnace structure 1 in any' suitable manner. The blowersmay be driven by individual'motors 23, only one of which is shown, which may be directly connected thereto in any suitable manner.

The intake side of each of the4 blowers may-be connected by a pipe or a conduit 24 to a pipe 25 extending across the bottom wall of the furnace and in close proximity to the openings thereof,` two pipes beine` located at each end of the furnace. The pipe 25 may be provided with aplurality of openings 26` through which air may enter (see Fig. 2).

The exhaust or discharge side 'of the. blowers 19 to 22, inclusive, may be connected to headers 27 extending laterally across the top wall of the furnace 1. The ends of the headers 27 may be connected to exhaust dischargepipes 28 and 29 located near the ceiling of the furnace structure and the middle portions of the headers may be connected to exhaust pipes 31. As shown, the ends of the exhaust pipes 28, 29 and3`1 are separated in order that the hooks 16 of the conveyor may pass through the furnace in the manner hereinbefore set forth. The pipes 28, 29 and 31 may be provided with a plurality of openings 32 through which air from the blowers may be'discharged.

In the preferred form of the invention` the blowers 19 to 22, inclusive, are of the low pressure large volume type, that is. they are Aadapted to deliver' a relatively large volume of air at low pressure.' As shown in Figs. 1 and 3 of the drawings. the air which is being discharged from the blowers is directed at an angle towards the center of the furnace structure 1. The air, as itleaves the pipes 28, 29 and 31, strikes against the relatively large volume of heated high velocity air indicated by the arrows 33 and causes the latter to move downwardly towards the bottom wall of the furnace and into the intake pipes 25. drawn through the blower and again discharged against the outwardly moving stream of heated air 33. The low pressure air is thus so circulated and recirculated The air is then that walls of low velocity, large volume, air

34 and 35 are provided at each end of the furnace adjacent to the open ends thereof.

It is to be noted that the walls 34 and 35 come in contact with the incoming cold air lrepresented by the arrows 36 and deiiect it downwardly into the pipes 25, therefore, the walls 34; and 35 not only check or prevent the heatedv air'33 from leaving the furnace chambers, but they also check or prevent the cold air 36 from entering the furnace chamber beyond the pipes 25 located .farthest in the lfurnace chamber.

'For purposes of illustration, it may be assumed that six units of cold air are entering.,V

`the furnace 1 as shown in Fig. 3 of the drawings. Then it may be assumed that three of these units are checked by the walls 35 and thatthree of these units continue. two of them being drawn into the pipes 25 connected to the blowers 19 and 20, respectively,

and the sixth runit continuing into the hot region or middle portion of the furnace..

The air is here heated, wherefore it rises to the top of the furnace chamber and increases in volume, which volume may be represented by the summation of thfarrows 33. As shown. the heated air travels outwardly towards the open .ends of the furnace.`

Again, it may be assumed that three units of the'heated air 33 are ,directed downwardly by the walls 34 into thepipes 25 connected to-theblowers 2O and 21,` three of them continuing to the walls 35, .two of which are directed downwardly into the pipes 25 connected 'to the blowers'19 and 22, respectively. Therefore, one unit of air escapes to the atmosphere. 1 f

By providing two wallsI or screens of circulating air`34 and 35 at each end of the furnace, it has, by example, beenY shown that, whereas six units of air would ordinarily enter the furnace chamber-land be heated and circulate out into the atmosphere, by utilizing the walls of airfor checking or preventing the air from entering` the furnace from the atmosphere` only one unit of air has been heated. In utilizing these walls of air (by example), only 1/; of the amount of air is heated as compared with the furfrom the atmosphere-into the furnace with the result that efficiency of the furnace is increased.

With proper spacing of the walls of air 34 and 35, one Wall will checkA the circulation of rair from the atmosphere through the furnace, while the other wall strikes o r contacts with heated material, carried by the hooks 16 on conveyor 12, and is deflected into the chambers 3 onto cold material carried by the hooks on the conveyor track 13, it bein understood that the conveyor tracks 12 an 13 move in opposite directions so that when cold work is entering at one end of the furnace, hot work is leaving at the same end. ForA example, when material carried by the hooks 16 strikes or Vpasses through the walls of air 34, the air is disparsed and caused to churn or swirl within the chamber to such an extent that the air heated by the material carried on the hooks is blown. over to the material carried, b the hooks in the chamber 3. While this air eing swirled and churned about, the wall remains intact and prevents heated air escaping to the atmosphere. By the ime the material has reached the walls 35, W ll 34 will have become intact and i nform again when the walls 35 become 1isrup'ted and dispersed by the material. this case, .the walls 35 tend to prevent ee of heated air to the atmosphere.

it is preferable to use low velocity, me walls of air for eheclring the and egress ofair from the atmosthe furnace chamber, it is to be L that high velocity, relatively lmewallsof air may be utilized herein described has beenmade to an openended furnace of the tunnel type, the invention maybe applied to furnaces having only vone opening where economy permits.

In a furnace provided with heating means Q 'and an opening through which work may be inserted and withdrawn from the furnace, in combination, an'intake pipe located at the top of the furnace chamber, an" exhaust pipe located at the bottom of 'the furnacev chamber, means for drawing air through the intake pipe and exhausting it throuvh the exhaustpipe, and means for directing the air so drawn and exhausted across the incoming and outgoing streams of Atold and heated air so that awall of air is provided wl'ierebythe streams tending to enter and leave at the bottom and top of the furnace chamber are substantially checked from penetrating the furnace beyond the air wall.

In testimony whereof, we have hereunto subscribed our names this 14th Aday of March, i928.

oRANsToN H. CARPENTER. ALVIN n, KEENE.

(IERTEF'ECATE F CGRRECTION.

Paen Flo. 725,129, August 2G, 1929.

CRANSTON H. CARPENEll, ET AL.

l is hereby certified that erxm' appears im ihe primed Specific: foi Gf le above Vumheed patent requiring @,:mreciion as ollows: Page 3, ne 65, rhe claim, i531 "mp" read "hmmm", and e 66, for "bottom" rrad "mgfg and that Ehe sa Letters Patent shud be read with 'hee corrsaimls .'hereiu that the same may confm'm to the record rh@ cass in the Patent Office.

Sgne and seaied this 28th day of February, A. D. 1933.

w M. ,L Moore {heal} Acting Commissioner qof Patents. 

